Gusty winds this weekend with elevated fire weather concerns

Gusty winds, dry fuels and low humidity may lead to elevated fire weather conditions with easier fire starts and rapid spread of new or existing fires. Near normal temperatures and dry conditions for the next week. Widespread smoke should start pushing out of the valley this weekend.

Discussion

NorCal is under short-wave ridging early this morning, behind the departing trough now over the northern Rockies and ahead of the next short-wave sliding down the BC coast. Skies remain clear across the area except for widespread smoke from the wildfires.

Surface pressure gradients are mostly a little weaker compared to 24 hours ago, but the MFR-RDD gradient is up slightly and is presently around 6.5 mbs. A few northerly gusts of around 15-20 mph are occurring across the northern Sacramento Valley and surrounding foothills, and local northeast gusts of 20-30 mph are present again across the higher elevations of the northern Sierra.

The highest concentrations of wildfire smoke are over the northern half of the Sacramento Valley and across the northern Sierra and foothills. A moderate Delta Breeze has brought some improvement into the southern Sacramento Valley. However, northerly flow along the west side of the Sacramento Valley may bring an increase in smoke to the Sacramento region again today as the Delta Breeze temporarily weakens.

Stronger onshore flow is forecast to develop tonight as the upstream short-wave approaches. This should bring an improvement in air quality to the Sacramento region. The remainder of the Central Valley is expected to see improvement on Saturday as stronger westerly flow associated with the trough pushes much of the smoke off to the east.

This trough is forecast to slide east through the PacNW over the weekend with less digging than the last system. The higher elevations of the northern Sierra and southern Cascades will see gustier southwest winds over the weekend which could pose problems for the Dixie Fire. Otherwise, dry weather with temperatures close to average is expected to continue.

Extended Discussion (Tuesday through Friday)

Upper level troughing remains over Northern California through much of next week. High temperatures will gradually increase through the extended period, but remain mostly near normal values for mid to late August. Smoke will continue to influence day to day highs. Dry weather and periods of breezy onshore flow continue next week.